So far this month, from October 1 - October 10, we have had 545,940 users between mobile and tablet, with 693,840 sessions. Our average CTR across all platforms is 0.19% this month, with an average this year of 0.22%.
I can't give you an exact timeline for when you would reach the impressions that a $2,500 spend would get, but at the current monthly average in October, you'd be looking at reaching that spend in just over 1 day at $5 CPM, and 2.5 days at $2 CPM.